I have a 2001 X Star. I have got about half a dozen small yellow pumps for the ballast system witch consist of two 750 lbs in the rear lockers, center ballast and then the integrated bow sack under the seats. Everything was exactly like this when I bought the boat last year. I am always running into issues with the pumps getting what seems like "air locked" when trying to fill them. I have never had any issues with emptying them though. I have considered upgrading all the fill pumps with the Tsunami 1200 GPH pumps. Any one else run into the same type of problems?
I am not in a huge rush as I am waiting for my new motor to get built so I can get it back on the water soon!
Thanks in advance!

I have the same ballast configuration on my 05 X2 (same hull as yours.) Somewhere between 01 and 05 MC switched to reversible pumps for each ballast tank/sac. Much simpler. I've never had any problems with mine. You might want to consider that option.

The reason you're sucking air is because your intakes are at the transom. Each bag/tank has it's own 3/4 thru hull back then. When the boat is running the exhaust blows air pockets into the pump fill area this creating those air pockets. Try filling with the engine off. I swapped my two side tank pumps in my 2000 ( had all the yellow as you do) to Tsunami 1200 from wakemakers , but that required all new hoses and was a complete overhaul. Almost halved my fill times to my 750's I also added a reversible Johnson pump to fill my bow sac. While that is 750 gph vs the 1200 tsunamis , it fills the 650 bow sac little faster than the tsunamis fill the 750's . If I had to do it again I would spend the extra on the reversible Johnson pumps from Wakemakers and go to a one pump, reversible style as it seems to be way more efficient as it doesn't loose force when the bag keeps getting full. I think the tsunami may loose a little force as the sac starts to get full and not force as much pressure to keep it flow rate. Just speculation on my end

Since the motor is out the optimal transition would be change those 3/4 through huls in the transom to 1 inch if you can. Go with the reversible Johnson or jabsco pump and run the 1inch hose. This would be the most efficient and fastest fill rate.

Second fastest ...... Keep all the 3/4 fittings and factory hoses but add two reversible pumps for the side tanks

I have the same ballast configuration on my 05 X2 (same hull as yours.) Somewhere between 01 and 05 MC switched to reversible pumps for each ballast tank/sac. Much simpler. I've never had any problems with mine. You might want to consider that option.

The issue with changing the diameter on the transom intakes is that the floor/hull will get on the way with a bigger backing nut and the wider intake diameter. I really think if you just eliminate the aerator pumps, and threw a Johnson reversible in there your flow rate would be better than the aerators. You could come off that 3/4 intake immediately add a 3/4-1inch hose adapter and viola. Now you have 1inch hose which is the biggest factor. Sure the 3/4intake wil have a small restriction, but the punk would be able to "suck" the water trough there to get you more flow rate than the stock